On dispersion halos of typomorphic indicator elements at the Semiluzhenskoye ore occurrence (Tomsk Oblast)
Abstract Generated abstract
This paper reports geochemical prospecting results from the Semiluzhenskoye antimony ore occurrence in Tomsk Oblast, situated within the Kolarovo, Semiluzhenskaya fault zone. Mercurometric and metallometric surveys of mercury and associated indicator elements, including barium, strontium, and zinc, identify primary and secondary dispersion halos in the Kamenka, Mezhovka, Malka, and Kirgizka river areas. Mercury contents commonly exceed background by one to three orders of magnitude, with the Kamenka, Mezhovka sector showing the strongest anomalies, while barium broadly follows mercury, strontium shows an inverse relation, and zinc gives a less distinct but generally supportive pattern. The study concludes that the occurrence is promising for concealed antimony and possibly mercury, antimony mineralization, likely at depths not exceeding about 600 to 700 m.
Full Text
ON DISPERSION HALOS OF TYPOMORPHIC INDICATOR ELEMENTS AT THE SEMILUZHENSKOYE ORE OCCURRENCE
(TOMSK OBLAST)
G. M. IVANOVA
(Presented by the scientific seminar of the Department of Petrography)
Antimony–mercury mineralization, rather widely developed in the region, is apparently confined to the Kolarovo–Semiluzhenskaya fault zone of north-northeastern strike, which here cuts through Lower Carboniferous deposits.
The presence of this zone is confirmed by occurrences of antimony and mercury within it. In the northern part of the zone lies the Semiluzhenskoye bedrock antimony ore occurrence, within which we carried out a mercurometric survey, as well as a metallometric survey for a number of associated indicator elements (barium, strontium, zinc). The following results were obtained.
The background mercury content in the rocks was determined as \((1–2)\cdot 10^{-6}\%\). The mercury content in antimonite ore and in rock with antimonite at the Semiluzhenskoye ore occurrence is given in Table 1.
As a result of the work carried out in the area described, in the Mezhovka–Kamenka sector a broad primary dispersion halo of mercury was identified. In fact, all samples from this sector have mercury contents above background. Of particular interest are sites on the right bank of the Kamenka River opposite the eastern outskirts of the village of Semiluzhki, near a place somewhat below the bridge on the highway. Here the mercury content in samples is \(5\cdot 10^{-3}\%\), which is 3 orders of magnitude above background. Also of interest is the slope of Mount Krutaya on the right bank of the Kamenka River, where the mercury content in samples is likewise elevated—from \(1\cdot 10^{-4}\) to \(5\cdot 10^{-3}\%\), which is 3 and 2 orders of magnitude above background. In general, within the halo the mercury content in most samples ranges from \(3\cdot 10^{-5}\%\) to \(5\cdot 10^{-5}\%\), which is also a whole order of magnitude above background.
If one takes into account that, usually around a deposit or ore occurrence, mercury contents are 2 orders of magnitude higher than background for antimony–mercury deposits and 1 order higher for antimony deposits (N. A. Ozerova, 1962), and that in halos of deposits the mercury content varies from millionths to hundredths of a percent, more often amounting to \(1\cdot 10^{-4}\%\), then, apparently, this sector is undoubtedly of interest—especially if one considers the excellent data obtained here from heavy-mineral-concentrate sampling. Judging from the prevailing mercury content in samples of \(3\cdot 10^{-5}\) to \(5\cdot 10^{-5}\%\), according to the data of N. A. Ozerova and V. P. Fedorchuk, one may assume possible ore potential of this sector at a depth of no more than 500–700 m (Fedorchuk V. P., 1964; Ozerova N. A., 1962).
In places with elevated mercury content, the ore occurrence lies—
Table 1
| No. | Sample No. | Location | Content, % antimony | Content, % mercury |
|---|---|---|---|---|
| 1 | 1a | Antimonite dumps in the bed of the Kirgizka River | 10 (75) | \(1\cdot10^{-4}\) |
| 2 | 2 | Borehole 63, depth 4–5 m | 4 | \(1\cdot10^{-4}\) |
| 3 | 1 | Borehole 60, depth 1–2.5 m | 3 | \(5\cdot10^{-5}\) |
| 4 | 1 | Borehole 61, depth 1 m | \(8\cdot10^{-1}\) | \(3\cdot10^{-5}\) |
| 5 | 1 | Borehole 66, depth 4 m | \(3\cdot10^{-2}\) | \(3\cdot10^{-5}\) |
| 6 | 1 | Borehole 63, depth 2–4 m | \(2\cdot10^{-2}\) | \(5\cdot10^{-5}\) |
lies at a shallower depth, or in terms of the content of ore components it is higher.
Analysis of samples in the Malka area showed that the secondary dispersion halo of mercury here has contents that are not low for it: namely, it ranges from \(3\cdot10^{-5}\) to \(1\cdot10^{-5}\%\), which is also a full order of magnitude higher than the background content. The fact deserves attention that this is quite substantial for a secondary dispersion halo.
Finally, in the area of the Kirgizka River, a primary dispersion halo of mercury has also been identified; it is not as clearly expressed as in the area of the Mezhovka—Kamenka rivers, but in most samples of this halo the mercury content is from \(1\cdot10^{-5}\) to \(3\cdot10^{-5}\%\), which is also one order of magnitude higher than the background content. Only in individual samples in the area of the bridge across the Kirgizka River does the mercury content rise sharply from \(1\cdot10^{-4}\%\) to \(7\cdot10^{-5}\)—\(5\cdot10^{-5}\%\). All this indicates that the possibility of mineralization in the area clearly exists, but it is blind and at depths of no less than 500–700 m, and here, possibly, even deeper.
The dispersion halos of barium rather accurately repeat, in all areas, the dispersion halos of mercury. The barium content in antimonite ore and in rock with antimonite at the Semiluzhenskoye ore occurrence is shown in Table 2:
Table 2
| No. | Sample No. | Location | Content, % antimony | Content, % mercury | Content, % barium |
|---|---|---|---|---|---|
| 1 | 1a | Antimonite dumps in the bed of the Kirgizka River | 10 (75) | \(1\cdot10^{-4}\) | \(2\cdot10^{-1}\) |
| 2 | 2 | Borehole 63, depth 4–5 m | 4 | \(1\cdot10^{-4}\) | \(1\cdot10^{-1}\) |
| 3 | 1 | Borehole 60, depth 1–2.5 m | 3 | \(5\cdot10^{-5}\) | \(1\cdot10^{-1}\) |
| 4 | 1 | Borehole 61, depth 1 m | \(8\cdot10^{-1}\) | \(3\cdot10^{-5}\) | \(5\cdot10^{-2}\) |
| 5 | 1 | Borehole 66, depth 4 m | \(3\cdot10^{-2}\) | \(3\cdot10^{-5}\) | \(1\cdot10^{-1}\) |
| 6 | 1 | Borehole 63, depth 2–4 m | \(2\cdot10^{-2}\) | \(5\cdot10^{-5}\) | \(1\cdot10^{-1}\) |
The background content of barium in the rock has been determined as \(1\cdot10^{-2}\%\). In the dispersion halos in all areas, barium is usually present in amounts of \(1\cdot10^{-1}\%\) and \(2\cdot10^{-1}\%\) in those places where an elevated mercury content has been found. Where mercury is lower, the barium content in the samples also decreases to \(5\cdot10^{-2}\%\), more rarely to \(3\cdot10^{-2}\%\).
The dispersion halos of strontium, which has an inverse dependence with mercury, confirm the halos identified by mercury. This is especially clearly visible in the area of the Kamenka—Mezhovka rivers; a less clear picture is observed on the Malka River. Possibly this is connected with the fact that on
Malka we are dealing with a secondary dispersion halo. Thus, usually, where elevated mercury contents in the rocks occur, strontium has not been detected by spectral analysis, or its very lowest content, \(2 \cdot 10^{-2}\%\), has been encountered. In places where there is little mercury, the strontium content rises to \(3 \cdot 10^{-2}\%\), \(4 \cdot 10^{-2}\%\). This confirms V. P. Fedorchuk’s conclusions about the presence and accumulation of strontium in horizons poor in ore mineralization.
The zinc content in antimonite ore and in rock with antimonite is presented in Table 3.
The background content was determined as \(1 \cdot 10^{-3}\%\). The zinc dispersion halos as a whole confirm the general picture in the areas, although not as clearly as barium. The predominant part of the samples in the Kamennka–Mezhovka rivers area gives zinc contents of \(1 \cdot 10^{-2}\%\), which undoubtedly indicates contamination of the area as a whole, but individual specific enriched places, as with mercury and barium, are not identified by the zinc halo in this area. In the Malka River area the zinc dispersion halo, like, incidentally,
Table 3
| No. | Sample No. | Location | Antimony content, % | Mercury content, % | Zinc content, % |
|---|---|---|---|---|---|
| 1 | 1a | Antimonite dumps on the Kirgizka River | 10 (75) | \(1 \cdot 10^{-4}\) | \(8 \cdot 10^{-3}\) |
| 2 | 2 | Borehole 63, depth 4–5 m | 4 | \(1 \cdot 10^{-4}\) | \(1 \cdot 10^{-2}\) |
| 3 | 1 | Borehole 60, depth 1–2.5 m | 3 | \(5 \cdot 10^{-5}\) | \(8 \cdot 10^{-3}\) |
| 4 | 1 | Borehole 66, depth 4 m | \(3 \cdot 10^{-2}\) | \(3 \cdot 10^{-2}\) | \(5 \cdot 10^{-3}\) |
| 5 | 1 | Borehole 92, depth 1–12 m | \(5 \cdot 10^{-5}\) | \(5 \cdot 10^{-3}\) |
mercury and barium, confirms a somewhat elevated halo against the general background—this is the left bank of the Malka River near its mouth, and also the left bank of the Kamenka River near the mouth of the Malka River. Here samples with zinc contents of \(1 \cdot 10^{-3}\%\) and \(5 \cdot 10^{-2}\%\) mainly predominate. It must be taken into account, however, that the dispersion halo on the Malka River is secondary, while the background content is given for a primary dispersion halo. In the Kirgizka River area, contents of \(5 \cdot 10^{-3}\%\) and \(1 \cdot 10^{-2}\%\) predominate; no clear picture emerges here.
Conclusions
The geochemical studies carried out make it possible to draw the following conclusions:
-
The area of the Semiluzhenskoye ore occurrence is clearly promising with respect to antimony and even, probably, mercury-antimony mineralization. This is evidenced by mercury dispersion halos with contents 1–2 and even 3 orders of magnitude higher than the background content. This is also indicated by the behavior and dispersion halos of the indicator elements—companions.
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Of all three investigated areas, the most interesting appears to be the Kamennka–Mezhovka rivers area, where the general mercury dispersion halo has mercury contents of \(3 \cdot 10^{-5}\) to \(5 \cdot 10^{-5}\%\), and in some individual places indicated above, mercury is present in amounts from \(1 \cdot 10^{-4}\) to \(5 \cdot 10^{-3}\%\), which is 2 and 3 orders of magnitude above the background content.
Also of interest is the Malka River area, although what we studied here was not a primary mercury dispersion halo, but a secondary one. It appears that in this area there is some contamination by mercury. Here, against the general background
one should single out the left slope of the Malka and Kamenka rivers near the mouth of the Malka River.
- The dispersion halos of mercury, in terms of their contents, showed that the mineralization here is clearly concealed and, moreover, at depths possibly not exceeding 600–700 m.
These conclusions could be drawn thanks to the experience gained in numerous works in recent years at deposits of Central Asia, the Middle Urals, Transcarpathia, and elsewhere, on the study of primary dispersion halos of mercury at antimony, antimony–mercury, and mercury deposits. Experience has shown that, among the various typomorphic indicator elements, mercury is the most reliable indicator not only at mercury deposits but also within the limits of non-mercury deposits, in particular antimony deposits (N. A. Ozerova, V. P. Fedorchuk).
REFERENCES
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N. A. Ozerova. Primary dispersion halos of mercury. Problems of Geochemistry, IV, issue 72. Publishing House of the Academy of Sciences of the USSR, Proceedings of IGEM, 1962.
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V. P. Fedorchuk. Methods of Prospecting and Exploration for Concealed Mercury–Antimony Mineralization. Moscow, Nedra Publishing House, 1964.